Insights into Higher Alcohols Selectivity Modulation of CuLa/Al2O3 Catalyst for Ethanol Upgrading

Abstract The structure‐performance relationship of the CuLa/Al 2 O 3 catalyst for ethanol upgrading to higher alcohols was established with a focus on the Cu + /Cu 0 ratios and acidity. Due to the strong metal‐oxide interaction and the La promotion, the Cu species were highly dispersed and existed in the forms of Cu + and Cu 0 with the former as main phase. The Cu + /Cu 0 ratios increased with the decrease of reduction temperatures and the high Cu + contents led to the increase of ethyl acetate selectivity dramatically. The high reduction temperature also enhanced the acidity of CuLa/Al 2 O 3 catalysts. The strong Lewis acid sites of the sample reduced at 823 K worked as an efficient catalyst for the intermolecular dehydration of ethanol and promoted the formation of diethyl ether. For other samples, the higher alcohols selectivity and yield increased linearly with the medium acidity, indicating that the medium acidity was the critical influence factor of the higher alcohols formation for the CuLa/Al 2 O 3 catalysts in the present study and the determining step should be the aldol condensation catalyzed by the medium acid sites.